[Effects of curcumin on apoptosis of pulmonary fibroblasts from rats].

OBJECTIVE: To investigate the effect of curcumin on apoptosis of pulmonary fibroblasts from rats and the molecular mechanisms. METHODS: Twenty 6 week old male SD rats were randomly divided into 2 groups with 10 rats in each group: the normal control group (NLF) and the model group (MLF). The pulmonary fibrosis models were made by intratracheally instillation of bleomycin. The rats were sacrificed on the 28 day of experiment, and the pathologic changes of the lung tissues were investigated. Fibroblasts were derived from lung tissues and were cultured in vitro. Then the cells were treated with curcumin at different concentrations (5, 10, 20 and 40 micromol/L). TUNEL staining was used to detect apoptosis. The Caspase-3 and Caspase-8 expression of each group were determined by flow cytometry (FCM). The expression changes of apoptosis-regulating proteins of Caspase-9 in cells were examined by immunohistochemical staining. RESULTS: In the MLF group treated with 4 different concentrations of curcumin for 12 h, apoptotic morphological changes were observed in the cells. Apoptotic index (AI) was (30.17 +/- 0.53)%, (37.20 +/- 0.25)%, (45.12 +/- 0.31)%, (51.90 +/- 0.27)% respectively, which were significantly higher than that of the control group without curcumin (4.59 +/- 0.19)%. The expression of Caspase-3 was (53.1 +/- 0.7)%, (60.5 +/- 0.6)%, (69.1 +/- 0.9)%, (74.9 +/- 0.7)%, which were significantly higher than that of the control group (5.5 +/- 0.8)%. The expression of Caspase-8 were (37.2 +/- 0.5)%, (46.8 +/- 0.4)%, (56.5 +/- 0.3)%, (67.3 +/- 0.3)%, which were significantly higher than that of the control group (4.6 +/- 0.6)%. The expression of Caspase-9 were (39.38 +/- 0.88)%, (47.51 +/- 0.24)%, (57.75 +/- 0.63)%, (68.36 +/- 0.29)%, which were significantly higher than that of the control group (4.92 +/- 0.34)%. Curcumin did not induce apoptosis of NLF, the expressions of Caspase-3, Caspase-8, Caspase-9 being not statistically different from that of the control group without curcumin. CONCLUSIONS: Curcumin can induce apoptosis of pulmonary fibroblasts in rats with bleomycin-induced pulmonary fibrosis and the mechanism may be related to the activation of Caspase-3, Caspase-8, and Caspase-9.